查询词典 lactonization

Vanillin 58 was used as starting material, which underwent methylation, bromination, acetalization, lithiation followed by nucleophlic addition to aldehyde, Diels-Alder reaction, selective reduction and lactonization to produce diphyllin in an overall yield of 38%(7 steps).

这个方法从香兰素58开始，经过甲基化、溴化、成乙二醇缩醛反应、锂化而后对醛亲核加成、Diels-Alder反应、选择性还原反应和内酯化反应共7步，最后得到diphyllin，总产率38％。

Lactonization of 32 swiftly took place under basic condition, and the first four-ring intermediate 53 was gained.

以动力学烯醇化-氧化的方法，在18的〓位引入了〓羟基，解决了构成1，4-内酯环的相对立体化学问题。32在碱性条件下，顺利完成了1，4-内酯环的构筑，首次获得了四环中间体53。

Ruthenium-modified solid catalyst Ru-Co2-CeO2 was applied to the lactonization of diols in the presence of molecular oxygen and achieved highly efficient catalytic performance.

将钌改性的固体催化剂Ru-Co2-CeO2用于以分子氧作为氧化剂的二元醇的催化氧化内酯化反应中，发现该催化剂具有很好的催化反应性能。

Second, the acid-promoted lactonization was abandoned in favor of a strong base protocol, thereby eliminating the modest decomposition, presumably arising via loss of the TBS groups in both the starting material and the lactone.

其次，酸内酯被提拔强烈主张废弃基地协议，从而消除了适度分解、经产生的损失大概在TBS的团体和内酯原料。

The diastereo-selective lactones 57～58 was obtained by the polyfluoroalkyl -lactonization of S--2-methyl-4-pentenoic acid under the reaction conditions mentioned above.

以S--2-甲基-4-戊烯酸进行上述内酯化反应，可得到具有立体选择性的产物57a，57b，58a，58b。

Based on the concepts of fragrance chemistry, under the guidance of molecules structure and odour relationships, we synthesized a list of potential odorants 46a-s, 47a-b, 48a-d and 49a-e by esterification, lactonization and reduction of the Ireland-Claisen rearranged products. Some of them were evaluated.

四、基于合成香料化学目前发展的现状，以香料的分子结构对香气影响的一些规律为指导，对所获得的部分Ireland-Claisen重排产物羧酸进行结构修饰，合成了系列潜香分子46a-s，47a-b，48a-d及49a-e，并进行了评香。

Such structural complexity is further enhanced by O-acetylation, esterification, lactonization, as well as other forms of substitutions, reflecting significance of carbohydrates in cell recognition.

细胞表面上糖缀合物的糖链经常以多/寡聚体形式存在，并且结构复杂，常常大量表达唾液酸、糖醛酸、硫酸化糖基等酸性糖，并发生O-乙酰化、酯化和内酯化等修饰。

Based on our intensive studies on the lactonization of oligo/polysialic acids, we proposed for the first time that the lactone-ring formation of oligo/polysialic acids has three stages. We also provided a novel model to explain the conformational changes of oligo/polysialic acids caused by the repulsing forces among the carboxyl groups of sialic acid residues. Our results should provide novel approaches for further investigation of the structural-functional relationships of oligo/polysialic acids.

在对多/寡聚唾液酸内酯化过程进行深入研究的基础上，于国际上率先提出多/寡聚唾液酸内酯的形成具有三个阶段的观点，并首创性地提出了羧基排斥所致多/寡聚唾液酸分子空间构象改变的模型，为深入研究多/寡聚唾液酸结构与功能的关系提供了新生长点。

Simvastatin is a cholesterol lowering agent that is partially synthesized from lovastatin. Simvastatin is an inactive lactonization precursor parmaceutical, it operate by active metabolites or its derivatives via liver hydrolyzation.

辛伐他汀是疗效确切的调血脂药物，能有效降低冠心病的发病率和死亡率，已列入国家基本药物，在冠心病的一级和二级预防中，作为治疗高胆固醇血症的首选药物。

The first synthetic route uses 1,2,4-trimethoxybenzene and chloroacetonitrile in forming 2,4,5-trimethoxy-a-chlor-acetophenone under the anhydrous condition, then the intermediate condensates with papaverine forming the core pyrro[2,l-a]isoquinoline, followed by formation and lactonization to form the lactone ring. The second synthetic route uses prepared aldehyde with prepared ethyl nitroacetate by Knoevenagel condensation to obtain 2-Nitro-3-(2,4,5-tris-methoxy-phenyl)-acrylic acid ethyl ester and 2-Nitro-3-(2,4,5-tris-benzyloxy -phenyl)-acrylic acid ethyl ester etal intermediates. The lamellarin skeleton could arise from condensation of the papaverine and these intermediates by Michael reaction, the ester group is provided for subsequent lactonization. The third synthetic route uses coumarin or indan-l,3-dione derivatives and papaverine to form lamellarin under basic conditions.

第一条路线首先从1，2，4-三甲氧基苯出发与卤乙腈作用合成卤代芳酮中间体，然后与罂粟碱反应合成开链片螺素，最后经乙酰化、去保护、成内酯环得到片螺素；第二条路线由制备的芳醛和制备的硝基乙酸乙酯经缩合得到2-硝基-3-芳基丙烯酸乙酯，然后由该中间体与罂粟碱反应，在完成关环的同时也引入酯基，最后去保护、成内酯环得到片螺素；第三条路线是由香豆素或茚二酮出发，经溴代后的中间体与罂粟碱反应，得到片螺素的基本框架。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。